TARGET  RANGE  POCKET  BOOK 

FOR  USE  WSTH  THE 

U.  S.  MAGAZINE  RIFLE 

MODEL  OF  1303.  CAL.  .30 

APRIL  23,  1908 


o 


GIFT  OF 


XO.  1998 


TARGET  RANGE  POCKET  BOOK 

FOR  USE  WITH  THE 

U.  S.  MAGAZINE  RIFLE 

MODEL  OF  1903,  CAL.  .30 


7  PLATES 


\j\  £. 

APRIL  28,  1908 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1917 


32 


TARGET  RANGE  POCKET  BOOK. 

I.  This  pamphlet  has  been  prepared  especially  for 
use  with  the  service  rifle,  model  of  1903,  on  the  target 
range.     The  tables  contained  herein  refer  to  the  above- 
mentioned  rifle  equipped  with  the  model  of  1905  sights, 
graduated  for  the  ball  cartridge,  caliber  .30,  model  of 
1906.     The  data  given  in  the  tables  have  been  either 
determined  experimentally  for  the  average  rifle  under 
standard    conditions    or    computed,    using    constants 
obtained  experimentally. 

II.  Blank  columns  have  been  left  in  the  tables  for 
the  addition  of  such  data  peculiar  to  any  particular 
rifle,  as  may  be  desired  by  the  marksman.     Great  care 
is  taken  in  the  manufacture  of  the  rifle  to  insure  its 
uniformity  and  excellence,  but  so  many  variables  enter 
into  the  shooting  of  a  rifle  that  a  certain  amount  of 
deviation  from  the  average  inevitably  results. 

III.  The  bore  of  the  U.  S.  magazine  rifle  is  drilled, 
reamed,  straightened,  and  rifled  with  the  utmost  of 
mechanical  and  personal  skill  and  the  barrel  is  finally 
stocked  and  targeted  in  order  to  test  its  actual  shooting 
qualities. 

In  targeting,  each  rifle  is  required,  at  a  range  of  200 
yards,  to  place  the  center  of  impact  of  all  shots  well 
within  a  vertical  strip  7  inches  wide.  Too  much  care 
can  not  be  exercised  in  preserving  the  barrel  and  bore 
of  the  rifle  in  good  condition.  The  main  points  to  be 
observed  are : 

1.  To  keep  the  bore  clean  and  well  oiled  so  as  to 
avoid  rust. 

363418  8 


4  TARGET  RANGE  POCKET  BOOK. 

2.  To  avoid  the  use  in  the  bore  of  emery  cloth  or  any 
other  harsh  abrasive. 

3.  To  protect  the  lips  of  the  muzzle  of  the  barrel 
from  deformation. 

4.  To  protect  the  stock  from  moisture  and  consequent 
swelling. 

The  above  points  are  all  important  factors  in  the 
good  shooting  of  the  rifle  and  should  be  carefully 
observed  by  all  who  desire  to  obtain  the  best  results. 

IV.  The  following  method  of  cleaning  the  bores  of 
small  arms  has  been  practiced  at  the  Springfield  Ar- 
mory for  a  number  of  years  with  good  results :  As  soon 
as  practicable  after  firing,  using  the  brass  cleaning  rod 
and  cloth  patches  (preferably  canton  flannnel)— 

First.  Thoroughly  clean  the  bore  with  patches 
soaked  in  a  saturated  solution  of  sal  soda. 

Second.  Remove  the  soda  from  the  bore,  using  dry 
patches. 

Third.  Oil  the  bore,  using  patches  saturated  with 
cosmic  oil. 

Fourth.  About  twenty-four  hours  after  this  cleaning 
repeat  the  three  operations  just  mentioned. 

This  second  cleaning  is  necessary,  no  matter  how 
carefully  the  first  cleaning  is  done,  for  the  reason  that 
the  powder  gases  are  probably  occluded  by  the  steel 
under  the  heavy  chamber  pressure  and  are  not  reached 
by  the  first  cleaning.  . 

After  the  second  cleaning  and  oiling  the  rifle  may 
be  stored  indefinitely  in  a  reasonably  dry  place  without 
fear  of  any  deterioration  of  the  bore. 

V.  True  metallic  fouling  consists  of  a  thin  film  of 
cupro  nickel,  which  is  abraded  from  the  bullet  jacket 
and  deposited  on  the  bore.     Contrary  to  the  usual  idea, 


TARGET  RANGE  POCKET  BOOK.  5 

it  has  been  found  that  this  film  does  not  affect  the 
accuracy  of  the  rifle  and  is  in  no  way  detrimental. 
On  the  contrary,  it  is  if  anything,  beneficial,  inasmuch 
as  it  offsets  the  erosion  to  a  minute  degree.  The  thick- 
ness of  this  fouling  after  several  thousand  rounds  is 
less  than  ".0001.  The  stripping  of  a  considerable  por- 
tion of  the  jacket  in  the  bore  is  not  properly  called 
metallic  fouling,  but  is  a  metallic  obstruction,  which 
should  be  removed  by  the  bullet-jacket  extractor  de- 
scribed in  Form  1923,  if  practicable,  or  if  not,  the  rifle 
should  be  turned  in  to  an  armory  or  ordnance  depot. 

VI.  The  table  on  page  57  of  the  Description  and 
Kules  for  the  Management  of  the  U.  S.  Magazine  Rifle, 
Model  of  1903,  .30  caliber,  shows  three  columns  or  sets 
of  deviations  of  the  bullet.  The  first  column  shows 
the  path  of  the  bullet  as  projected  on  a  horizontal 
plane  when  firing  with  the  line  of  sight  coincident 
with  a  vertical  plane  through  the  axis  of  the  bore.  In 
this  column  the  deviation  is  to  the  left  up  to  500  yards. 
This  is  due  to  the  lateral  jump  or  whip  of  the  barrel. 
The  second  column  shows  the  amount  of  deviation  cor- 
rected for  by  the  inclination  of  the  drift  slot  in  the 
rear  sight  leaf.  The  third  column  is  the  difference 
between  the  first  and  second,  shows  how  the  rifle  shoots 
with  the  model  of  1905  sight,  or  the  amount  of  drift 
which  is  not  automatically  corrected. 

The  following  table  shows  how  the  average  rifle  shoots 
when  issued  to  the  service: 

Example:  Under  standard  conditions,  with  the  sight 
set  at  800  yards,  zero  deflection,  and  aiming  at  the 
center  of  a  target  800  yards  away,  the  bullet  will  strike 
1.9"  to  the  right  of  the  point  aimed  at. 


TARGET  RANGE  POCKET  BOOK. 

TABLE  I  (Drift). 


Range. 

Deviations. 

Deviations. 

Left. 

Right. 

Left. 

Right. 

Yards. 
100 

200 

300 
400 

500 
600 

700 
800 

900 
1,000 

Inches. 
.0 

.0 

.0 
.0 

.0 

Inches. 

.0 
.0 

.6 
1.9 

4.0 
6.7 

Inches. 

Inches. 

VII.  Deviations  due  to  wind  are  computed  by  the 
formula: 

S  =  (t-~hc  Wsinfl 

in  which 

5  =  deviation  at  target  in  inches. 

t  =  time  of  flight  for  range  considered. 

R  =  range  in  yards. 

V  =  muzzle  velocity  in  feet  per  second. 

C  =  a  constant  =  10.44. 

W  =  velocity  of  wind  in  feet  per  second. 

6  =  inclination  of  the  direction  of  the  wind  to  tra- 

jectory. 


TARGET  EANGE  POCKET  BOOK. 


It  may  be  noted  that  the  wind  effect  is  less  for  the 
model  of  1906  ammunition  than  for  the  model  of  1903 
ammunition,  formerly  used  with  the  U.  S.  magazine 
rifle,  model  of  1903.  This  is  largely  due  to  the  shorter 
times  of  flight  which  obtain  with  the  former.  The  de- 
viations for  the  model  of  1906  cartridge  are  tabulated 
in  Table  II  below  for  a  1-mile-an-hour  III  or  IX  o'clock 

wind. 

Table  II  (Wind). 


Range. 

Deviation. 

Deviation. 

Yards. 
100 

Inches. 
0.1 

Inches. 

200 

.3 

300 

.8 

400 

1.5 

500 

2.4 

600 

3.6 

700 

5.1 

800 

6.9 

900 

9.1 

1,000 

11.5 

VIII.  The  rear  end  of  the  movable  base  of  the  model 
of  1905  sight  bears  graduations,  the  value  of  the  small- 
est graduation  being  about  3.99  inches  at  100  yards. 
These  smallest  graduations  are  known  as  "points"  of 
deflection  or  windage.  The  following  table  shows  the 


TARGET  RANGE  POCKET  BOOK. 


lateral  correction  caused  at  the  target  by  setting  off  one 
point  of  deflection: 

Table  III  (Deflection). 


Range. 

Correction 
at  target. 

Correction 
at  target. 

•  Yards. 
100 

Inch(s.* 
4 

Inches. 

200 

8 

300 

12 

400 

16 

500 

20 

600 

24 

700 

28 

800 

32 

900 

36 

1,000 

40 

*An  exact  point  of  windage,  as  stated  above,  is  equivalent  to  about 
3". 99  at  100  yards,  but  no  appreciable  error  is  made  up  to  1,000  yards 
by  considering  the  point  equal  to  4  inches,  and  calculation  is  sim- 
plified thereby. 

IX.  When  firing  at  a  given  range,  if  the  rear  sight 
slide  is  raised  by  an  amount  corresponding  to  25  yards 
of  range,  the  point  of  impact  of  the  bullet  at  the  target 
is  raised  by  a  certain  number  of  inches.  The  follow- 
ing table  shows  how  much  the  point  of  impact  is  raised 
or  lowered  by  a  change  of  25  yards  in  the  sight  setting. 


TARGET  RANGE  POCKET  BOOK. 


TABLE  IV  (Elevation). 


Range. 

Correc- 
tion at 
target. 

Correc- 
tion at 
target. 

Yards. 

100 

Inches. 
0.7 

Inches. 

200 

1.6 

300 

2.8 

400 

4.3 

500 

6.2 

600 

8.6 

700 

11.6 

800 

15.4 

900 

19.9 

1,000 

25.1 

X.  Table  II,  page  7,  of  this  pamphlet  shows  how 
much  the  bullet  is  deflected  by  a  1-mile-an-hour  wind 
blowing  directly  across  the  range  from  III  or  IX 
o'clock.  If  the  same  wind  blows  from  the  II,  IV,  VIII, 
or  X  o'clock  directions,  the  resulting  deflection  of  the 
bullet  is  less  than  when  the  wind  blows  directly  across 
the  range,  and  to  obtain  these  deflections  the  deflections 
in  Table  II  are  multiplied  by  the  cosine  of  30  degrees, 
or  .866+  .  Similarly  if  the  same  wind  blows  from  the 
I,  V,  VII,  or  XI  o'clock  directions  the  resulting  de- 
flection is  still  less,  and  to  obtain  these  deflections  the 
deflections  in  Table  II  are  multiplied  by  the  cosine 
of  60  degrees,  or  .5.  In  other  words,  a  1-mile-an-hour 
wind  blowing  from  I,  V,  VII,  or  XI  o'clock  directions 


10 


TARGET  RANGE  POCKET  BOOK. 


has  just  half  the  deflecting  power  of  the  same  wind 
blowing  from  the  III  or  IX  o'clock  directions. 

To  counteract  or  compensate  for  wind  deflection  a 
certain  number  of  points  of  deflection  must  be  set  off 
on  the  rear  sight.  The  following  table  shows  how 
many  points  must  be  used  at  the  various  ranges  for  a 
10-mile-an-hour  wind  from  each  of  the  various  direc- 
tions. 

Since  the  deflecting  power  of  a  wind  is  directly  pro- 
portional to  its  velocity,  the  proper  corrections  for  any 
velocity  of  wind  may  be  readily  computed  from  the 
following  table: 

TABLE  V  (Wind,  Lateral). 
Points  of  windage  necessary  to  correct  a  10-mile-an-hour  wind. 


Range. 

III  or  IX. 

ii,  rv, 

VIII,  or 
X. 

I,  V, 
VII,  or 
XI. 

in  or  IX. 

II,  IV, 
VIII,  or 
X. 

I,V, 
VII,  or 
XI. 

Yards. 
100 

Points. 
0.2 

Points. 
0.2 

Points. 
0.1 

Points. 

Points. 

Points. 

200 

.4 

.4 

.2 

300 

.7 

.6 

.3 

400 

.9 

.8 

.5 

500 

1.2 

1.0 

.6 

600 

1.5 

1.3 

.7 

700 

1.8 

1.6 

.9 

800 

2.2 

1.9 

1.1 

900 

2.5 

2.2 

1.3 

1,000 

2.8 

2.4 

1.4 

TARGET  EANGE  POCKET  BOOK.  11 

XI.  Winds  blowing  from  the  XII  and  VI  o'clock 
directions  have  no  deflecting  influence  on  the  flight  of 
the  bullet;  but  these  winds  have  the  effect  of  shortening 
(in  the  case  of  XII  o'clock  winds)  or  lengthening  the 
range  (in  the  case  of  VI  o'clock  winds).  Or,  to  put  it 
in  another  way,  a  wind  blowing  directly  down  the  range 
from  the  firing  point  toward  the  target,  has  the  effect 
of  raising  the  point  where  the  bullet  strikes  the  target. 
Similarly,  a  wind  blowing  directly  up  the  range  toward 
the  firing  point  has  the  effect  of  lowering  the  point 
where  the  bullet  strikes  the  target. 

The  following  table,  showing  the  effects  of  these 
winds,  has  been  computed,  using  Colonel  Ingall's  for- 
mula: 

±AX  =  C{S(v±Wp)-S(V±Wp)}-(X±TWp) 
and  the  approximate  relation : 

±Ay  =  ±AX  tan  o> 

The  following  table  shows  effects  of  XII  and  VI 
o'clock  winds  blowing  10  miles  per  hour.  For  other 
wind  velocities,  the  corrections  may  be  readily  com- 
puted without  appreciable  error  by  assuming  that  these 
corrections  are  directly  proportional  to  the  wind  veloci- 
ties. The  longitudinal  wind  effects  of  I  and  II  o'clock 
winds  may  be  found  by  multiplying  the  figures  in  the 
table  by  .866  and  .5,  respectively. 


12 


TARGET  RANGE  POCKET  BOOK. 

TABLE  VI  (Wind,  Longitudinal). 


Corrections  for  10-mile-an-hour  wind. 

Range. 

VI 
yards  over 
at  target. 

XII 
yards 
short  at 
target. 

VI 
inches 
above  at 
target. 

XII 

inches 
below  at 
target. 

Yards. 
100 

1.0 

0.9 

.03 

.02 

200 

2.0 

2.0 

.12 

.11 

300 
400 

3.2 
4.5 

3.2 

4.4 

.41 
.69 

.40 
.68 

500 

6.1             6.0 

1.4 

1.3 

600 

8.0            8.0          2.5 

2.4 

700 

10.2 

9.9          4.4 

4.3 

800 

13.6          13.3 

7.8 

7.6 

900 

19.9          19.0       14.7 

14.1 

1,000 

26.7          25.5       25.1 

23.9 

NOTE. — The  correction  in  sight  elevation  in  yards  correspond- 
ing to  inches  above  or  below  may  be  read  from  the  second  or 
third  columns  of  this  table. 

XII.  The  following  diagrams  illustrate  graphically 
the  values  of  the  point  of  deflection  and  of  the  elevation 
corrections  on  the  several  standard  targets  at  the  several 
ranges  prescribed  in  Small-Arms  Firing  Regulations, 
1906. 


TARGET  RANGE  POCKET  BOOK.  13 

Plate  I  simply  illustrates  how  the  value  of  any  cor- 
rection on  the  sight  increases  with  the  range. 

Plate  II  shows  the  value  of  the  point  of  deflection 
on  the  ;; A'7  target  at  a  range  of  200  yards.  This  dia- 
gram also  shows  the  value  at  the  target  of  a  change  of 
sight  setting  of  50  yards. 

To  illustrate  the  method  of  using  this  and  the  sub- 
sequent diagrams,  let  it  be  supposed  that  a  shot  was 
fired  at  the  "A"  target  at  a  range  of  200  yards  and 
that  the  bullet  struck  at  the  point  marked  "P"  (Plate 
II) ,  then  the  correction  necessary  to  bring  the  next  shot 
on  the  center  of  the  bulPs-eye  may  be  read  directly  from 
the  diagram,  thus:  75  yards  less  elevation  and  2  points 
of  deflection  to  the  left. 

WAR  DEPARTMENT, 

OFFICE  OF  THE  CHIEF  OF  ORDNANCE, 

Washington,  April  28,  1908. 
FORM  No.  1998. 
Ed.  June  13-17-5,000. 
26791— O— 1587. 


105406—17- 


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Correction  corresponding  to  a  change  of  elevation  of  25  yards. 


Correction  corresponding  to  a  change  of  elevation  of  25  yards. 


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